Kovakromipinnoitus

Kovakromipinnoitus, also known as hard chrome plating, is an electrochemical deposition process used to apply a hard, wear-resistant chromium coating onto a substrate. This coating is typically applied to metal parts to improve their durability, reduce friction, and enhance corrosion resistance. The process involves immersing the workpiece, which acts as the cathode, in a chromic acid-based electrolyte solution. Anode bars, typically made of lead alloys, are also submerged in the solution and connected to a DC power supply. When current is applied, chromium ions from the electrolyte are reduced and deposited onto the cathode surface.

The thickness of the hard chrome coating can vary significantly depending on the application, ranging from a few micrometers to several millimeters. The hardness of the coating is exceptionally high, typically falling within the range of 60-70 HRC (Hardness Rockwell C). This superior hardness makes it ideal for components subjected to abrasive wear, such as hydraulic cylinders, engine parts, molds, and tooling.

Beyond its wear resistance, hard chrome plating offers excellent corrosion protection, especially in environments prone to chemical attack. The coating is dense and non-porous, forming an effective barrier against corrosive agents. Furthermore, the low coefficient of friction associated with hard chrome plating helps to minimize surface wear and improve the efficiency of moving parts. Despite its numerous benefits, the process requires careful control of parameters like current density, temperature, and electrolyte composition to achieve optimal coating properties and prevent defects.